國家地理:鴕鳥蛋·豺狼·禿鷹

Here we are on the Serengeti Plain in Africa, where an ostrich has abandoned an egg and a hungry jackal means to make a meal out of it. What we’ve got here is a highly motivated animal trying and failing to figure out this culinary conundrum. It’s just a little too big, a little too slippery, a little too everything for the jackal. There’s three pounds of food in there, and it’s gonna stay in there, right? Not if this Egyptian vulture has anything to do with it.
These birds are always on the lookout for edible orbs in jackal-proof packaging. Ostrich eggs are an important source of protein, and this vulture has a strategy to get at its contents. The Egyptian vulture is one of the few birds in the world that figure out how to use a stone as a tool. Some scientists feel that this isn’t intelligence so much as highly evolved instinct. Whatever it is, it works. The vulture finally cracks a hole big enough for its beak. The vulture is one step closer to mealtime than the jackal, but it’s not home free yet. You see, here on the Serengeti, the sound of a cracked eggshell is like a newsflash. The word is out, and other diners are ready to line up.
A tawny eagle shows up to share in the bounty. But an even bigger customer is about to appear. Check out this lappet-faced vulture. Would you wanna mess with this bird? At nearly four feet tall, it’s the largest, most aggressive vulture on the Serengeti. When it comes to a food find like this, pecking order is strictly observed. The biggest bird gets the booty.
現(xiàn)在我們在非洲大草原上。一只鴕鳥剛剛下了一個蛋，一只饑餓的豺狼瞄準了這只蛋，決定美餐一頓。但是，這只興致勃勃的動物打錯了算盤。這只蛋太大了，太滑了，總之對他來說什么都不利。這可是重達三磅的食物啊，它會一直都在這里的，對嗎?當然，如果這只埃及禿鷹不介入的話。
這些禿鷹一直在盯這可以吃的豺狼保護著的鴕鳥蛋。鴕鳥蛋蛋白質(zhì)非常豐富，而且禿鷹有非凡的策略可以知道硬殼里面的蛋。埃及禿鷹是世界上為數(shù)很少的懂得利用石頭作為工具的鳥類之一。有些科學家感到，這只是經(jīng)過高級進化的本能，而不是智慧。無論這是什么，只要管用就行了。禿鷹終于在鴕鳥蛋上鑿了一個洞，可以使嘴巴伸進去。禿鷹的美餐比豺狼快了一步，但是還不能放松警惕。你看，在非洲大草原上，啃噬蛋殼的聲音就像一個簡短的新聞報道。一旦發(fā)出聲音，其他獵食者也想分得一杯羹。
一只黃褐色的鷹跑來分享這頓美餐。但是一個更大的不速之客即將到來。看看這只垂頭喪氣的禿鷹。你想和這只鳥發(fā)生沖突嗎?這只鳥大約六尺高，是非洲大草原上最大，最具攻擊性的禿鷹。獵食的時候總是遵循這個嚴格的規(guī)律，體型最大的鳥得到戰(zhàn)勝品。